.\" $OpenBSD: bsd.port.arch.mk.5,v 1.8 2013/08/10 10:17:36 miod Exp $
.\"
.\" Copyright (c) 2011 Marc Espie
.\"
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.Dd $Mdocdate: August 10 2013 $
.Dt BSD.PORT.ARCH.MK 5
.Os
.Sh NAME
.Nm bsd.port.arch.mk
.Nd ports tree Makefile fragment, concerned with arch issues
.Sh SYNOPSIS
.Bd -literal
# Set up such as
MULTI_PACKAGES = -main -special
ONLY_FOR_ARCHS-special = i386
.Ed
.Pp
.Fd .include <bsd.port.arch.mk>
.Bd -literal
#some more lines such as
\&.if ${BUILD_PACKAGES:M-special}
CONFIGURE_ARGS += --enable-special
\&.endif
.Ed
.Pp
.Fd .include <bsd.port.mk>
.Sh DESCRIPTION
.Nm
holds the logic used for arch-dependent builds in the ports tree.
It is normally included as part of the larger
.Xr bsd.port.mk 5 ,
but it is also available separately for ports that require it.
.Bl -bullet
.It
multi-packages ports that need to remove some subpackages based
on pseudo-flavors or architecture constraints.
.It
ports that need to make explicit tests on arch-dependent constants.
.El
.Pp
.Nm
assumes the following variables are already defined:
.Bl -tag -offset indent -compact -width ONLY_FOR_ARCH-<sub>
.It MULTI_PACKAGES
.It FLAVOR
.It FLAVORS
.It PSEUDO_FLAVORS
.It Ev NOT_FOR_ARCHS[-<sub>]
.It Ev ONLY_FOR_ARCHS[-<sub>]
.El
and optionally, if the default won't be appropriate
.Bl -tag -offset indent -compact -width ONLY_FOR_ARCH-<sub>
.It Ev NO_SHARED_LIBS
.It Ev IGNORE[-<sub>]
.El
.Pp
It will set up the following variables for use in the rest of the
.Pa Makefile :
.Bl -tag -offset indent -compact -width ONLY_FOR_ARCH-<sub>
.It Ev ARCH
.It Ev ALL_ARCHS
.It Ev APM_ARCHS
.It Ev BE_ARCHS
.It Ev COMPILER_VERSION
.It Ev GCC3_ARCHS
.It Ev GCC4_ARCHS
.It Ev LE_ARCHS
.It Ev LP64_ARCHS
.It Ev NO_SHARED_ARCHS
.It Ev NO_SHARED_LIBS
.It Ev PROPERTIES
.It Ev IGNORE-<sub>
.It Ev BUILD_PACKAGES
.El
.Pp
Most importantly,
.Ev BUILD_PACKAGES
will be correctly set up, taking
.Ev ONLY_FOR_ARCHS[-<sub>]
and
.Ev NOT_FOR_ARCHS[-<sub>]
limitations into account, as well as pseudo-flavors.
.Pp
Note that thanks to the way
.Xr make 1
variables are evaluated, a setup such as
.Bd -literal -offset indent
ONLY_FOR_ARCHS-foo = ${LP64_ARCHS}
\&.include <bsd.port.arch.mk>
.Ed
.Pp
is perfectly admissible, since
.Ev ONLY_FOR_ARCHS-foo
will be used only after
.Ev LP64_ARCHS
is defined.
.Pp
Also, you do not need to explicitly include
.Pa bsd.port.arch.mk
just to define
.Bd -literal -offset indent
ONLY_FOR_ARCHS = ${LP64_ARCHS}
.Ed
.Pp
since
.Pa bsd.port.mk
does define arch constants before evaluating
.Ev ONLY_FOR_ARCHS .
A more detailed description of each variable is available in
.Xr bsd.port.mk 5 .
.Pp
All the constant values
.Ev ARCH , ALL_ARCHS , COMPILER_VERION ,
.Ev GCC3_ARCHS , GCC4_ARCHS , LP64_ARCHS , NO_SHARED_ARCHS
and
.Ev PROPERTIES
are also available from
.Ev MODULES
and from
.Pa ${.CURDIR}/../Makefile.inc .
Note that due to historical accident,
.Ev NO_SHARED_LIBS
is not such a constant.
Test
.Ev PROPERTIES
to assert whether a given platform supports shared libraries.
.Sh SEE ALSO
.Xr bsd.port.mk 5
.Sh HISTORY
.Nm
was split from
.Xr bsd.port.mk 5
in
.Ox 5.1 .
